ZOBODAT - www.zobodat.at Zoologisch-Botanische Datenbank/Zoological-Botanical Database Digitale Literatur/Digital Literature Zeitschrift/Journal: Veröffentlichungen des Naturkundemuseums Erfurt (in Folge VERNATE) Jahr/Year: 2006 Band/Volume: 25 Autor(en)/Author(s): Tillack Frank, Scheidt Ulrich, Ihle Thomas Artikel/Article: First record of Blakeway's mountain snake, Plagiopholis blakewayi Boulenger, 1893, from Thailand, with remarks on the distribution od Plagiopholis nuchalis (Boulenger, 1893) (Reptilia: Squamata: Colubridae, Pseudoxenodontinae) 181-186 Veröffentlichungen Naturkundemuseum Erfurt 25/2006 S. 181–186 First record of Blakeway‘s mountain snake, Plagiopholis blakewayi Boulenger, 1893, from Thailand, with remarks on the distribution of Plagiopholis nuchalis (Boulenger, 1893) (Reptilia: Squamata: Colubridae, Pseudoxenodontinae) FRANK TILLACK, Berlin*; ULRICH SCHEIDT, Erfurt & THOMAS IHLE, Lieskau Abstract Introduction We present a first record of Plagiopholis blakewayi from Thailand. The specimen was found at an altitude The genus Plagiopholis BOULENGER, 1893, comprises of about 2000 m a.s.l. on the margin of a primary five species (blakewayi, delacouri, nuchalis, styani alpine mist forest near the border with Myanmar. and unipostocularis), which are native to mountain- A detailed description of the specimen is provided. ous regions of Myanmar, China, Indochina (Laos and Compared with its sister species, Plagiopholis nucha- Vietnam) and Thailand (WELCH 1988). Plagiopholis lis, a substantial vicariance of the vertical distribution blakewayi Boulenger, 1893, has been recorded from is notable. P. blakewayi inhabits regions above 1300 the Chinese provinces of Guizhou, Sichuan and Yun- m a.s.l., whereas P. nuchalis lives mainly at lower nan (ZHAO & JIANG 1966, WU et al. 1985, JIANG & levels, at least where both taxa share the same distri- ZHAO 1992, ZHAO et al. 1998, ZHAO 2003) as well bution range. The records of P. nuchalis for Vietnam as from Kachin and Shan States in Myanmar (SMITH require reexamination. 1943). For Thailand, only Plagiopholis nuchalis (Bou- lenger, 1893) had been known to date (NABHITABHATA Zusammenfassung et al. 2004, DAVID et al. 2004). Erstnachweis von Blakeway’s Bergschlange, Pla- Methods giopholis blakewayi Boulenger, 1893, für Thailand, mit Bemerkungen zur Verbreitung von Plagiopho- The description of the body colouration is based on lis nuchalis (Boulenger, 1893) (Reptilia: Squamata: the preserved specimen. The numbers of dorsal scale Colubridae, Pseudoxenodontinae) rows are given for at a point one head length behind Wir berichten über den ersten Nachweis von Pla- head, at midbody, and at one head length before the giopholis blakewayi für Thailand. Das Tier wurde vent, respectively. Ventrals were counted according in einer Höhe von ca. 2000 m NN am Rand eines DOWLING (1951). Values for symmetric head scala- primären Hochgebirgsnebelwaldes nahe der Grenze tion characters are given in left/right order. For a zu Myanmar gefunden. Eine ausführliche Beschrei- comparison of the variation of measurements and bung des Exemplar ist gegeben. Zur Schwesterart some scalation characteristics in P. blakewayi, data Plagiopholis nuchalis zeichnet sich eine weitgehen- were summarized from literature (WALL 1925, SMITH de Vikarianz in der Höhenverbreitung ab. P. blake- 1943, ZHAO et al. 1998), and are given here in brack- wayi besiedelt Bereiche ab 1300 m NN, P. nuchalis ets behind our data. Abbreviations used are: SVL: lebt dagegen vorwiegend in tieferen Lagen, zumin- snout-vent length; TaL: tail length; TL: total length; dest im gemeinsamen Verbreitungsgebiet. Die für a.s.l.: above sea level. Vietnam gemeldeten Vorkommen von Plagiopholis nuchalis bedürfen einer Überprüfung. Results Keywords: Reptilia, Squamata, Colubridae, Pseu- During the course of an excursion conducted in doxenodontinae, Plagiopholis blakewayi, morphol- September of 2005, Plagiopholis blakewayi was for ogy; Plagiopholis nuchalis, Thailand, faunistics the first time collected in Thailand. The respective specimen was found at the Doi Pha Hom Pok, Chiang 181 Fig. 1. Plagiopholis blakewayi from Doi Pha Hom Pok, Provinz Chiang Mai, Thailand, 2000 m a.s.l. (NME R 496/06). Abb. 1. Plagiopholis blakewayi vom Doi Pha Hom Pok, Provinz Chiang Mai, Thailand, 2000 m ü NN (NME R 496/06). Fig. 2: Head close-up of Plagiopholis blakewayi (NME R 496/06). Abb. 2: Kopfstudie von Plagiopholis blakewayi (NME R 496/06). 182 Mai Province, northwestern Thailand, at an altitude of dorsals in the sacral region are weakly keeled (supra- about 2000 m a.s.l.. It has been deposited in the reptile cloacal keels). The ventrals number 117 plus 1 preven- collection of the Naturkundemuseum Erfurt, Germany tral [ 110-130,& 113-136]. They are wider than long, (NME R 496/06). unkeeled, and rounded at the outer margins. There are The morphological data and characteristics of both 24 divided subcaudals excluding the terminal scale [( colouration and pattern correspond largely with those 22-31, 18-28]. The anal scute is entire. The rostral is known from the literature (see, e.g., BOULENGER 1893, wider than high, extending far onto the upper side of the SMITH 1943, ZHAO et al. 1998, ZHAO 2003). Since head, and ending in a tip posteriorly. The portion of the detailed descriptions of P. blakewayi have been pub- rostral visible in dorsal view is longer by about 1/3 than lished only rarely in the past, we will give a thorough the suture between the internasals. The two internasals description of the Thai specimen (Fig. 1 + 2) in the are wider than long. The two prefrontals are distinctly following. wider than long, extend onto the sides of the head, and It is an adult male with a TL of 345 mm (SVL 307 mm, are in contact with the frontal, supraoculars, preoculars TaL 38 mm) [max. TL males 420 mm, TL females 500 and the postnasal shields. The frontal is hexagonal in mm]. The body is round in cross section and has a stout shape, longer than wide, and is in contact with the pre- appearance. The tail is short (12.4% of the TL) and frontals, supraoculars and the parietals. The supraocu- slightly flattened below. The head is little distinct from lars are large and distinctly longer than wide. Both the neck. The dorsal ground colour is greyish brown parietals are longer than wide. The nasal is completely with an iridescent sheen. An indistinct, narrow, blackish divided. Pre- and postnasals are of about the same size. brown band is present on the nape of the neck; it has a The lower suture meets with the first supralabial. The chevron-shaped vertebral projection that points forward, naris is situated in the prenasal and directed laterally with the tip touching the posterior margins of the pari- and posteriorly. Loreal shields are wanting. The large etals. A longitudinal dorsolateral row of small, blackish preoculars number 1/1; they do not extend onto the brown, irregularly shaped spots runs the length of body upper side of the head. There are 2/2 postoculars, the and tail, spaced at a distance of three dorsal scales. The upper one of which is larger than the lower one. There majority of dorsals have light margins. In addition, the is one elongate anterior and posterior temporal shield dorsals on the flanks have black lower margins. The each, with the posterior one being slightly larger than overall effect is a finely reticulated pattern that covers the anterior one. The supralabials number 5/5, with the the entire dorsal side. The ventral basic colouration 3rd being in contact with the eye. The first one is the is a greyish white from the head to the tip of the tail. smallest and the 4th the largest. Of the 6/6 infralabials, Ventrals and subcaudals are speckled throughout with the 1st through 3rd are in contact with the anterior sub- irregular spots of varying size and have dark outer mar- maxillar. The infralabials of the first pair are separated gins that correspond to the dorsal ground colour. The from each other by the mental and the anterior pair of upper side of the head is uniform greyish brown without submaxillars. The mental is pentagonal in shape and any significant pattern. The rostral shield is lighter than distinctly wider than long. Submaxillars are present the upper side of the head and exhibits a blackish brown in two pairs, with the posterior one being only slightly spot on its tip. Both the supra- and infralabials are longer than the anterior one. The two scales making up cream-coloured with almost all vertical sutures being the posterior submaxillar pair are separated from each dark. Another dark, elongate spot is situated beneath other by a single intruding large gular scale. the eye in the upper portion of the third supralabial. The The hemipenes of the specimen are nearly completely eye is small with a round pupil. The distance between everted and 8.9 mm long. The everted outer genial the anterior margin of the eye and the tip of the snout organs are neither forked nor bilobed. At the lower equals more than twice the eye diameter. pedicel, the sulcus spermaticus is undevided but from The dorsal scales are smooth, arranged in 15:15:15 the truncal region onwards divided for more than two slightly sloping rows; they lack any apical pits. The thirds of the organ. Both branches of the sperm groove dorsals are very homogenous in both size and shape, are diverging and run towards the outer margins of and only the outermost row is slightly enlarged. A few the apex. Truncus and apex are covered with distict 183 Fig. 3. Habitat of Plagiopholis blakewayi at the collecting side. Abb. 3. Habitataufnahme der Fundstelle von Plagiopholis blakewayi. spines, that fade into spine-like skin papillae towards trees are fairly densely overgrown with epiphytes such the apex tip (most probabely corresponding to Smith´s as mosses, curtain-forming lichens, orchids and ferns. [1943: 326] term “calyculate”). On the lower truncus there are some medium sized spines which fade into Altitudinal distributions of Plagiopholis blakewayi few rows of microspines.